Advances in the application of extracellular vesicles derived from three-dimensional culture of stem cells

Stem cells (SCs) have been used therapeutically for decades, yet their applications are limited by factors such as the risk of immune rejection and potential tumorigenicity. Extracellular vesicles (EVs), a key paracrine component of stem cell potency, overcome the drawbacks of stem cell applications as a cell-free therapeutic agent and play an important role in treating various diseases. However, EVs derived from two-dimensional (2D) planar culture of SCs have low yield and face challenges in large-scale production, which hinders the clinical translation of EVs. Three-dimensional (3D) culture, given its ability to more realistically simulate the in vivo environment, can not only expand SCs in large quantities, but also improve the yield and activity of EVs, changing the content of EVs and improving their therapeutic effects. In this review, we briefly describe the advantages of EVs and EV-related clinical applications, provide an overview of 3D cell culture, and finally focus on specific applications and future perspectives of EVs derived from 3D culture of different SCs.

Exosomal hsa_circ_000200 as a potential biomarker and metastasis enhancer of gastric cancer via miR-4659a/b-3p/HBEGF axis

BACKGROUND

Exosome, a component of liquid biopsy, loaded protein, DNA, RNA and lipid gradually emerges as biomarker in tumors. However, exosomal circRNAs as biomarker and function mechanism in gastric cancer (GC) are not well understood.

METHODS

Differentially expressed circRNAs in GC and healthy people were screened by database. The identification of hsa_circ_000200 was verified by RNase R and sequencing, and the expression of hsa_circ_000200 was evaluated using qRT-PCR. The biological function of hsa_circ_000200 in GC was verified in vitro. Western blot, RIP, RNA fluorescence in situ hybridization, and double luciferase assay were utilized to explore the potential mechanism of hsa_circ_000200.

RESULTS

Hsa_circ_000200 up-regulated in GC tissue, serum and serum exosomes. Hsa_circ_000200 in serum exosomes showed better diagnostic ability than that of tissues and serum. Combined with clinicopathological parameters, its level was related to invasion depth, TNM staging, and distal metastasis. Functionally, knockdown of hsa_circ_000200 inhibited GC cells proliferation, migration and invasion in vitro, while its overexpression played the opposite role. Importantly, exosomes with up-regulated hsa_circ_000200 promoted the proliferation and migration of co-cultured GC cells. Mechanistically, hsa_circ_000200 acted as a "ceRNA" for miR-4659a/b-3p to increase HBEGF and TGF-β/Smad expression, then promoted the development of GC.

CONCLUSIONS

Our findings suggest that hsa_circ_000200 promotes the progression of GC through hsa_circ_000200/miR-4659a/b-3p/HBEGF axis and affecting the expression of TGF-β/Smad. Serum exosomal hsa_circ_000200 may serve as a potential biomarker for GC.

CircRNA: a rising star in gastric cancer

In recent years, a large number of circRNAs have been identified in mammalian cells with high-throughput sequencing technologies and bioinformatics. The aberrant expression of circRNAs has been reported in many human diseases including gastric cancer (GC). The number of GC-related circRNAs with validated biological functions and mechanisms of action is growing. CircRNAs are critically involved in GC cell proliferation, apoptosis, migration, and invasion. CircRNAs have been shown to function as regulators of parental gene transcription and alternative splicing and miRNA sponges. Moreover, circRNAs have been suggested to interact with proteins to regulate their expression level and activities. Several circRNAs have been identified to encode functional proteins. Due to their great abundance, high stability, tissue- and developmental-stage-specific expression patterns, and wide distribution in various body fluids and exosomes, circRNAs exhibit a great potential to be utilized as biomarkers for GC. Herein, we briefly summarize their biogenesis, properties and biological functions and discuss about the current research progress of circRNAs in GC with a focus on the potential application for GC diagnosis and therapy.